Agonist regulation of human beta2-adrenergic receptor mRNA stability occurs via a specific AU-rich element.
Prolonged agonist stimulation of beta2-adrenergic receptors results in receptor down-regulation, which is closely associated with a reduction of the corresponding mRNA, an effect mediated in part by changes in mRNA stability. Transfection experiments with human beta2-adrenergic receptor cDNAs bearing or lacking the untranslated regions suggested that the essential agonist sensitivity of the mRNA resides within the 3'-untranslated region. The importance of this region was further confirmed in gel shift experiments; cytosolic preparations from agonist-stimulated DDT1-MF2 smooth muscle cells caused a shift of beta2-adrenergic receptor mRNAs containing the 3'-untranslated region. Progressive 3'-terminal truncations of the receptor cDNA led to the identification of an AU-rich element at positions 329-337 of the 3'-untranslated region as the responsible cis-acting element. Substitution of this motif by cytosine residues almost completely abolished mRNA down-regulation and inhibited the formation of the RNA-protein complex. Even though the beta2-adrenergic receptor AU-rich element showed two U --> A transitions compared with the recently proposed AU-rich element consensus sequence, it revealed an almost identical destabilizing potency. Fusion of the beta2-adrenergic receptor 3'-untranslated region to the beta-globin coding sequence dramatically reduced the half-life of the chimeric transcript in an agonist- and cAMP-dependent manner. This suggests that the agonist-induced beta2-adrenergic receptor mRNA destabilization is regulated by cAMP-dependent RNA-binding protein(s) via a specific AU-rich element.
Danner
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Institute of Pharmacology, University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany.
Frank
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Lohse
M J
MJ
D058666:Adrenergic beta-2 Receptor Agonists; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D018076:DNA, Complementary; D015536:Down-Regulation; D005914:Globins / Q000235:genetics; D006801:Humans; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D058666:Adrenergic beta-2 Receptor Agonists; D000318:Adrenergic beta-Agonists; D018076:DNA, Complementary; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D018343:Receptors, Adrenergic, beta-2; D011993:Recombinant Fusion Proteins; D005914:Globins